On the first level, climb the left side of the first tree you come to, climb to the very top. Now press 'P' to pause the game and type "ACEVIEWFROMUPHEREMATE" and the screens border will flash. Unpause the game and use the following keys:
'1-6'---Go to corresponding level with infinite energy
'W'-------------Gives you maximum weapon configuration
'E'----Takes you straight to the end of level gaurdian
'C'--------------------------Grants infinite continues
Or, on the high score table, enter one of the following:
"ASSASSIN"- | "THE ONE THE ONLY" | "SUPERFROG" | "ALIEN BREED"
"PROJECT X" | "PSIONIC SYSTEMS"
Enter "MIDAN" to continue from where you left off.